I got 2 and I have them for about 2 weeks. They sound good and you sound good, they connect immediately and have a good fit in the ear (at least in mine). They do not have a voice adjustment setting. The only negative thing is the talk time, you can't talk for more than 1 hour and if you connect it to 2 devices it takes around 35-45 seconds.

I have had it for 6 months and the battery now only lasts for a 5-10 minute call. With daily use, the battery used to last for half a day.
During calls, the other person's voice sounds very clear, but when I spoke, they often couldn't hear me, especially when driving with the window open. I had to close it for them to hear me clearly. I have tried several Bluetooth headsets, and compared to what I had before, this one is average in terms of usage and has the worst battery life.
On the positive side, it is very lightweight and fits nicely in the ear.
3 stars, considering the price.

Value for money. Connects to two devices simultaneously, very good sound and comfortable in the ear! Very good device!